The SitePoint Forums have moved.

You can now find them here.
This forum is now closed to new posts, but you can browse existing content.
You can find out more information about the move and how to open a new account (if necessary) here.
If you get stuck you can get support by emailing forums@sitepoint.com

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

As for the voting only once thing, you could store the ipnumber along with the vote in the db and then check for the exsiting ip number to be present in the db before putting a new vote in, at least would make sure noone votes from the same computer twice.

Please don't PM me with questions.
Use the forums, that is what they are here for.

on my rating system, what i do is logging both ip and addresses (like dialup165.sf.aol.com). the ip is used to avoid multiple rating (automatically) and the addresses are used to "manually" track cheaters. it's the best solution i think.

Incentives? Well, perhaps - but if you were to offer a prize of some sort, people would have to "register" somehow so you would have their contact information on hand assuming they "won."

You could, I suppose, just offer them access to some special area of the site for voting - they vote, are shown the results, and given a link, but they can "share" the link with others easily I'm sure.

Polls are best used to gather demographic data most of the time - a significant amount of traffic is required to make them work.

Nope, no polls on my sites right now - focusing more on content and such. The only recommendations I can give to try to increase poll participation is to make it clearly visible, and perhaps keep it somewhere on every page of your site.

In addition, going out of you way to ask interesting questions will help, as well taking away a "View Results" option - people will vote just to see where the vote total stands - I do that all the time.